Palms running with sweat. Throat dry. Chest pounding with anticipation. I had waited for this moment for more than a decade. It was 3pm on Wednesday, May 1 2002. Time for prime minister's questions and I was number three on the order paper, certain to be called by the Speaker.

Why all the excitement? It is just one wretched question, forgotten as soon as it is asked. And you get slapped down by the PM, who always has the last word. Yet it is your one chance to have a shot at the title. All the national and local press are watching. And it is the only time you rise to your feet when the chamber is packed -and baying for your blood.

PMQs have a special significance for me. Over 11 years ago I was plucked from Conservative central office, sent to No 10 and told to help on John Major's question time team. I had to scan the papers, work out the likely questions and think of killer facts and snappy one-liners.

Willing Conservative MPs were primed with helpful questions, hostile Labour members rebutted with points about tumbling unemployment figures or quotes from their militant past. It was better than working for a living.

And now all these years on, sitting on the green benches, it was finally my turn. What to ask? There are four types of question. First up is the "wife-beater". This is the question to which there is no answer. A typical effort would be: "What is the prime minister most proud of - the billion pounds wasted on the Dome or the million-pound bung from Bernie Ecclestone?"

In a different context, it was one of these that caught out Norman Lamont. A journalist asked him at a press conference what he regretted more, "singing in the bath or shopping at Threshers?". Norman's reply, "Je ne regrette rien", won laughter from hacks at the time but haunted him for years.

Next is "the teaser". This type of question looks limp and unexciting on paper, but can sometimes elicit the most interesting response by catching the prime minister off-guard. This parliamentary session's classic was from a Labour MP, Tony McWalter: "Could the prime minister briefly outline his political philosophy?" Tony Blair was completely stumped.

Third is the Daily Mail special. Pick the issue that the middle ranking tabloids are having kittens about and give it some oomph. Carjacking, the MMR vaccine and little baby Leo, etc. This week it would have been street crime or the May Day protests. Make it on to the front pages and enjoy 15 seconds of fame.

Finally, there are the local issues. These are by far the most boring for everyone else to listen to, easily the most effective. Unlike national papers, local ones actually report in some detail what members of parliament do. A short question can be followed up with a press release, an endless round of local TV and radio interviews and a prolonged burst of local stardom.

But is there any point to prime minister's questions? Critics say it is a charade in terms of accountability and claim that the jeering and finger pointing do more than anything else to give parliament and British politics a bad name. Questions are rarely answered and rational debate is impossible.

I don't agree - and I have now seen it from both sides of the fence.

In government, PMQs is the moment at which the prime ministerial tentacles stretch across Whitehall and ask every department to explain what it is doing and why. This is important in terms of ensuring accountability. Mr Blair knows he can be asked about anything - literally anything - and he needs answers. Even the bloated, spin-heavy No 10 machine built up by Blair is a minnow compared to the great departments of state.

Yet every Tuesday night and Wednesday morning, No 10 has to assert its authority and ensure it is happy with everything in Whitehall. In opposition, or from the backbenches, PMQs provide a chance to catch the government out or demonstrate its weakness on an issue.

Yesterday was no exception. Peter Viggers, the Conservative MP for Gosport, asked a simple question (a teaser) on the link between Gordon Brown's tax raid on pension funds and the fact that many companies are scrapping final salary pension schemes. Mr Blair was clueless and rambled on about reducing the national debt.

Bullseye. The No 10 machine would have known immediately that a better answer was required. Private secretaries at No 10 and the Treasury will now be drafting away. A small ripple, maybe, but the waters of government were disturbed none the less.

Perhaps the greatest strength of PMQs lies in what is perceived to be its greatest weakness. Yes, it is theatrical, even gladiatorial, with backbenchers waving and cheering like the crowds at the Circus Maximus. And that is the point. A prime minister or leader of the opposition who was slow-witted, corrupt or simply not up to the job would not survive. Before reformers suggest replacing the adversarial system with something more consensual and continental, they should ask themselves whether the continental politicians mired in corruption scandals would last for half an hour in the Commons on a Wednesday afternoon. I think not.

So what did I ask? What weakness did I probe? Half-baked plans to dock child benefit from truants? Soaring street crime in our capital? The Treasury select committee report that damns the chancellor and his Budget?

It was what defence buffs would call a "target-rich environment", but I went local, asking the prime minister to congratulate my Conservative-controlled district council for setting the lowest council tax in the country.

"Feeble!", I can hear you cry. "Ten years of waiting, just to pull the parish pump!" Well, there are 49 council seats up for election in West Oxfordshire today and I am in the business of trying to get people out to vote.